Optimized cultivation of highly-efficient degradation bacterial strains and their degradation ability towards pyrene

Two bacterial strains,Pyl and Py4,have been tamed and isolated through long cultivation with polycyclic aromatic hydrocarbon-pyrene as the single carbon source.It has been proven that they are both highly-efficient pyrene degrading bacteria and both Bacillus sp..The pyrene degradation ability of separated Pyl,Py4 and the consortium of equal Pyl and Py4 was studied in this project.It is shown that pyrene degradation rates were 88% in 10hr by Py1,84% in 14hr by Py4,and 88% in 8hr by the consortium.It was also determined that the best degradation temperatures were 37℃ and pH 7.0 respectively.The influence of different nutrient substrates added in the degradation experiments was also studied.It was shown that sodium salicylate,sodium acetate and yeast exuact had obvious simulative effect,but glucose had no obvious effect.     

Growth of Chlorinated Solvent‐Degrading Consortia in Fed‐Batch Bioreactors and Development of a Double‐Substrate High‐Performing Microbial Inoculum

The long‐term growth process of two microbial consortia effective in the aerobic cometabolic biodegradation of a mixture of 6‐chlorinated aliphatic hydrocarbons (CAHs), the effectiveness of these consortia as inocula for the bio‐augmentation of different types of microcosms and the development of a double‐substrate, high‐performing consortium is presented. The propane‐utilizing consortium generally proved to be the most effective one, being able to biodegrade vinyl chloride, cis‐ and trans‐1,2‐dichloroethylene, trichloroethylene, 1,1,2‐trichloroethane and 1,1,2,2‐tetrachloroethane at all the CAH concentrations tested (0–4 μM). Both consortia maintained unaltered CAH degradation capacities over a 300‐day growth period in the absence of the CAHs and were effective in inducing the rapid onset of CAH depletion upon inoculation in slurry microcosms set up with five types of aquifer materials. A consortium supplied with both methane and propane combined the best degradation capacities of the two single‐substrate consortia, and maintained stable performances for 150 days under slurry conditions. The degree of conversion of the organic Cl to chloride ions was equal to 90 %.     

The Distribution of Perkinsus marinus in Gulf Coast Oysters: Its Relationship with Temperature,Reproduction, and Pollutant Body Burden

Oysters from 48 Gulf of Mexico sites were examined for presence and infection intensity of the endoparasite, Perkinsus (= Dermocystidium) marinus (Mackin, Owen and Collier, 1950) as part of NOAA's Status and Trends Mussel Watch Program. Prevalence exceeded 75% at 25 sites. Infection intensity did not vary with sex or reproductive stage. Latitude, total polynuclear aromatic hydrocarbon (PAH) content and industrial and agricultural land use significantly affected the parasite's distribution. PAH and pesticide concentrations were latitudinally dependent, suggesting an impact of spawning frequency on uptake and depuration. P. marinus analysis complements the use of pollutant body burden for determining change in environmental quality because it responds differently than pollutant body burden to the biology and ecology of the oyster.     

Behavioural and chemical mechanisms behind a Mediterranean ant–ant association

1. Interspecific competition among ants is common, and so is competitive exclusion among dominant ant species. In contrast, specific associations between non‐parasitic ant species are rare, especially in the temperate zones. As an exception, the subordinate ant Camponotus lateralis frequently co‐occurs with the dominant Crematogaster scutellaris but rarely with other dominant ants. 2. This association is one of various associations between Camponotus and Crematogaster species across the world. However, the mechanisms behind these co‐occurences are largely unknown. 3. In the present study, we therefore investigated the association of Ca. lateralis and Cr. scutellaris. We studied the spatial association of the nests, interspecific aggression, both species' cuticular hydrocarbon profiles, and their propensity to follow the other species' pheromone trails. 4. Crematogaster scutellaris usually attacked and displaced the generally submissive Ca. lateralis, but was significantly less aggressive at jointly used trails. Camponotus nests were always in close proximity to Crematogaster nests. 5. The cuticular hydrocarbons of both species consisted of alkanes with chain lengths between C21 and C35. The two species had 25 hydrocarbons in common, including mono‐, di‐, and tetramethyl alkanes. Despite this qualitative similarity, however, the quantitative hydrocarbon composition differed between the two species. 6. Camponotus lateralis followed artificial trails containing trail pheromones of Cr. scutellaris, but the latter did not follow Ca. lateralis trail pheromones. Interspecific trail‐following by Camponotus, but not vice versa, has been observed in another Camponotus–Crematogaster association and may be a more general mechanism that facilitates associations between the two ant genera.     

Sexual dimorphism of arrestment and gregariousness in the bed bug (Cimex lectularius) in response to cuticular extracts from nymphal exuviae

Releaser pheromones have direct behavioural effects to arrest, attract or disperse insects, whereas interactions within groups of social insects are often influenced by primer pheromones. The behaviour of insects displaying intermediate levels of sociality is largely unexplored in this context. In the present study, both the gregariousness and arrestment (settling near the odour source) of bed bugs Cimex lectularius L. (Hemiptera: Cimicidae) in response to conspecific exuvial extracts are described. Adult males are arrested on filter papers with extracts derived from exuviae of fifth‐instar nymphs. Adult females and nymphs display no significant evidence for such behaviour. Adults of both sexes show no preference for extracts of male versus female fifth‐instar exuviae. Arrestment of adult males does not occur on papers treated with fourth‐instar exuvial extracts. Because the insects are assayed behaviourally in groups, an index is calculated describing how far bugs are away from being located independently of one another, as a measure of gregariousness. Adult males have lower values for this index (i.e. locations are closer to independence). Adult females, nymph cohorts and mixed age groups all have higher values for this index, which tend to increase over time. Females exhibit a clear increasing dose‐dependent relationship for this index. It is concluded that the extracts of fifth‐instar nymphal exuvia arrest males on refuges that possess the odour source. However, gregariousness is induced in females, without evidence of a tendency to assemble near the odour source.     

Extracellular oxidative enzyme production and PAH removal in soil by exploratory mycelium of white rot fungi

Selected strains of three species of white rot fungi, Pleurotus ostreatus, Phanerochaete chrysosporium and Trametes versicolor, were grown in sterilized soil from straw inocula. The respective colonization rates and mycelium density values decreased in the above mentioned order. Three- and four-ringed PAHs at 50 ppm inhibited growth of fungi in soil to some extent. The activities of fungal MnP and laccase (units per g dry weight of straw or soil), extracted with 50 mM succinate-lactate buffer (pH 4.5), were 5 to 20-fold higher in straw compared to soil. The enzyme activities per g dry soil in P. ostreatus and T. versicolor were similar, in contrast to P. chrysosporium, where they were extremely low. Compared to the aerated controls, P. ostreatus strains reduced the levels of anthracene, pyrene and phenanthrene by 81–87%, 84–93% and 41–64% within 2 months, respectively. During degradation of anthracene, all P. ostreatus strains accumulated anthraquinone. PAH removal rates in P. chrysosporium and T. versicolor soil cultures were much lower.     

Soil lipase activity – a useful indicator of oil biodegradation

The evaluation of soil lipase activity as a tool to monitor the decontamination of a freshly oil-polluted soil was tested in a laboratory study. An arable soil was experimentally contaminated with diesel oil at 5 mg hydrocarbons g^–1 soil dry weight and incubated with and without fertilization (N-P-K) for 116 days at 20°C. Lipase activity and counts of oil-degrading microorganisms were measured at regular time intervals, and the correlations with the levels of hydrocarbon concentrations in soil were investigated. The residual soil hydrocarbon concentration correlated significantly negatively with soil lipase activity and with the number of oil-degrading microorganisms, independent of fertilization. The induction of soil lipase activity is a valuable indicator of oil biodegradation in naturally attenuated (unfertilized) and bioremediated (fertilized) soils.     

Isolation and characterization of genes encoding polycyclic aromatic hydrocarbon dioxygenase from acenaphthene and acenaphthylene degrading Sphingomonas sp. strain A4

Sphingomonas sp. strain A4 is capable of utilizing acenaphthene and acenaphthylene as sole carbon and energy sources, but it is unable to grow on other polycyclic aromatic hydrocarbons (PAHs). The genes encoding terminal oxygenase components of ring-hydroxylating dioxygenase (arhA1 and arhA2) were isolated from this strain by means of the ability to oxidize indole to indigo of the Escherichia coli clone containing electron transport proteins from phenanthrene-degrading Sphingobium sp. strain P2. The translated products of arhA1 and arhA2 exhibited moderate sequence identity (less than 56%) to large and small subunits of dioxygenase of other ring-hydroxylating dioxygenases. Biotransformation with recombinant E. coli clone revealed the broad substrate specificity of this oxygenase toward several PAHs including acenaphthene, acenaphthylene, naphthalene, phenanthrene, anthracene and fluoranthene. Southern hybridization analysis revealed the presence of a putative arhA1 homologue on a locus different from that of the arhA1 gene. Insertion inactivation of the arhA1 gene in strain A4 suggested that the gene but not the putative homologue one was involved in the degradation of acenaphthene and acenaphthylene in this strain.     

Isolation and characterization of a novel sphingomonad capable of growth with chrysene as sole carbon and energy source

A bacterial strain able to grow in pure culture with chrysene as sole added carbon and energy source was isolated from PAH-contaminated soil after successive enrichment cultures in a biphasic growth medium. Initially, growth occurred in the form of a biofilm at the interface between the aqueous and non-aqueous liquid phases. However, after a certain time, a transition occurred in the enrichment cultures, with growth occurring in suspension and a concomitant increase in the rate of chrysene degradation. The strain responsible for chrysene degradation in these cultures, named Sphingomonas sp. CHY-1, was identified by 16S rDNA sequencing as a novel sphingomonad, the closest relative in the databases being Sphingomonas xenophaga BN6T (96% sequence identity). Both these strains clustered with members of the genera Sphingobium and Rhizomonas, but could not be categorically assigned to either genus. Sphingomonas sp. CHY-1 was characterized in terms of its growth on chrysene and other PAH, and the kinetics of chrysene degradation and 14C-chrysene mineralization were measured. At an initial chrysene concentration of 0.5 g l(-1) silicone oil, and an organic/aqueous phase ratio of 1:4, chrysene was 50% degraded after 5 days incubation and 97.5% degraded after 35 days. The protein content of cultures reached a maximum value of 11.5 microg ml(-1) aqueous phase, corresponding to 92 mg g(-1) chrysene. 14C-labelled chrysene was 50% mineralized after 6-8 weeks incubation, 10.7% of the radioactivity was incorporated into cell biomass and 8.4% was found in the aqueous culture supernatant. Sphingomonas sp. CHY-1 also grew on naphthalene, phenanthrene and anthracene, and naphthalene was the preferred substrate, with a doubling time of 6.9 h.     

Sesquiterpenes of the liverwort Scapania undulata

The essential oil of the liverwort Scapania undulata, collected in the Harz mountains, Northern Germany, was analysed by gas chromatography (GC), GC-mass spectrometry (MS) and several new components were isolated and investigated by various NMR techniques. As new natural compounds the sesquiterpene hydrocarbons (+)-helminthogermacrene (1) [the 4Z-isomer of germacrene A (9)], (-)-cis-beta-elemene (2) as a Cope-rearrangement product of 1, (+)-beta-isolongibornene (3) and (-)-perfora-1,7-diene (4) could be identified. 1 has an identical mass spectrum and identical GC retention time on a non-polar stationary phase as germacrene A (9) but is considerably more stable than the latter. The Cope-rearrangement of 1 proceeds slowly at 350 degrees C and (-)-cis-beta-elemene (2) is formed together with small amounts of other diastereoisomers.